Method for preparing anti-bacterial oxide film on the surface of aluminum materials

ABSTRACT

A method for preparing an anti-bacterial anodic oxide film on the surface of aluminum materials, comprising pretreatment, polishing, anodic oxidation, dyeing and sealing, wherein the surface of polished aluminum materials is smooth but has undulating waves and holes; in the dyeing after oxidation, a nano-sized dye is filled in the undulating waves and holes on the surface of aluminum materials, so if nano-silver is uniformly mixed in the dye in the process, the dye on the surface of aluminum materials will contain nano-silver finally and it will protect nano-silver from wearing during use; the dye-filled waves on the surface of aluminum materials are sealed via a sealing process finally, i.e., the dye is sealed in the surface of aluminum materials; at last, the surface of aluminum materials can be turned into desired colored patterns according to actual needs, and the nano-silver provides the anodic oxide film with anti-bacterial effect.

BACKGROUND OF THE INVENTION Technical Field

The present invention relates to the technical field of anodic oxidation of aluminum materials, and more especially, to a method for preparing an anti-bacterial oxide film on the surface of aluminum materials.

2. Description of Related Art

Aluminum materials such as aluminum and aluminum alloy have gradually become mainstream materials of electronic products and home decoration by virtue of their cost-saving and lightweight characteristics. In order to improve the wear resistance and corrosion resistance of aluminum products, the surfaces of these aluminum products are usually processed via anodic oxidation during which these products can be dyed for enhancement of their ornamental value. However, aluminum products frequently touched by people in life may become carriers of bacterial infection and bacteria on these aluminum products can only be disinfected by disinfectants usually, but the use of disinfectants brings more troubles and increases labor maintenance costs, therefore, an anti-bacterial anodic oxide aluminum product is in urgent need.

The anti-bacterial effect of nano-silver is always favored by people, and nowadays some nano-silver disinfectants are available on the market. However, they are not convenient for regular use, because they may bring more troubles and have high costs. And now there is no method of applying nano-silver into anodic oxide products of aluminum to provide the surface of anodized aluminum materials with an anti-bacterial effect.

BRIEF SUMMARY OF THE INVENTION

To solve the problem in the prior art where the anodic oxide films on the surface of aluminum materials are incapable of being anti-bacterial, the present invention provides a method for preparing an anti-bacterial anodic oxide film on the surface of aluminum materials.

A method for preparing an anti-bacterial oxide film on the surface of aluminum materials, comprising the following steps:

1) pretreatment: remove oil on the workpiece and clean the workpiece;

2) polishing: put the clean workpiece in an acid solution for chemical polishing;

3) anodic oxidation: put the chemically-polished workpiece in an acid tank for anodic oxidation;

4) dyeing: put the anodized workpiece in a dye tank which contains a nano-dye, wherein the mass fraction of nano-silver in the dye is 3%-5% and its diameter is not more than 100 nm;

5) sealing: seal the dyed workpiece via a high-temperature hydration or inorganic salt sealing method, and take out the sealed workpiece and dry it after cleaning.

In one embodiment, an ultrasonic vibration plate is provided at the bottom of the dye tank in Step 4).

In one embodiment, a bubble generator is provided at the bottom of the dye tank in Step 4) and dry and clean air is introduced into the bubble generator.

In one embodiment, the diameter of bubbles generated by the bubble generator is not more than 2 mm.

In one embodiment, the chemical polishing agent in Step 2) is nitric acid solution.

In one embodiment, sulfuric acid solution is used in the acid tank in Step 3).

In one embodiment, the workpiece is an aluminum or aluminum alloy workpiece.

The above-mentioned technical solution has the following effects: the surface of the polished aluminum materials is smooth but has undulating waves and holes; in the dyeing after oxidation, the dye is filled into the undulating waves and holes on the surface of the aluminum materials, because the dye is a nano-material, so if nano-silver is uniformly mixed in the dye in the process, the dye in the surface of the aluminum materials will contain nano-silver when finished and it will protect the nano-silver from wearing during use; the dye-filled waves on the surface of the aluminum materials are sealed via a sealing process when finished, i.e., the dye is sealed in the surface of the aluminum material; at last, the surface of the aluminum materials can be turned into the desired colored patterns according to the actual needs when finished, and the nano-silver provides the anodic oxide film on the surface of the aluminum materials with an anti-bacterial effect.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is further detailed in combination with the drawings and the embodiments as follows.

A method for preparing an anti-bacterial oxide film on the surface of aluminum materials, comprising the following steps:

1) pretreatment: remove oil on the work piece and clean the workpiece; 2) polishing: put the clean workpiece in an acid solution for chemical polishing; 3) anodic oxidation: put the chemically-polished workpiece in an acid tank for anodic oxidation; 4) dyeing: put the anodized workpiece in a dye tank which contains a nano-dye, wherein the mass fraction of nano-silver in the dye is 3%-5% and its diameter is not more than 100 nm; 5) sealing: seal the dyed workpiece via a high-temperature hydration or inorganic salt sealing method, and take out the sealed workpiece and dry it after cleaning. The mass fraction of nano-silver in the dye is the mass ratio of the formed anti-bacterial anodic oxide film on the surface of the workpiece; when the nano-silver content is less than 3%, the anti-bacterial effect is not good, while when the nano silver content is more than 5%, the cost is too high and the use may be incomplete, therefore, taking a comprehensive consideration, the nano-silver content is set to 3%-5% when finished.

In one embodiment, an ultrasonic vibration plate is provided at the bottom of the dye tank in Step 4). Nano-silver will sink when mixed in the dye, because it is a metal heavier than the dye; if the nano-silver sinks, the nano-silver is not easily taken by the dye onto the surface of the workpiece in the dyeing process; in order to avoid this situation, the ultrasonic vibration plate is provided at the bottom of the dye tank to prevent the nano-silver from sinking by way of vibration and improving the dyeing efficiency during the vibration process.

In one embodiment, a bubble generator is provided at the bottom of the dye tank in Step 4) and dry and clean air is introduced into the bubble generator. Because dry and clean air is introduced into the bubble generator, bubbles generated by the bubble generator are all dry and clean air when finished; in order to enhance the final anti-bacterial property of the anodic oxidation film, nano-silver has to be distributed uniformly in the dye, and air bubbles in the dye tank play a stirring role to facilitate the uniform distribution of the nano-silver in the dye.

In one embodiment, the diameter of the bubbles generated by the bubble generator is not more than 2 mm. Because both the dye and nano-silver are nano-materials, overly large bubbles cause a greater stirring force to be needed, are not conducive to the mixing of nano-silver in the dye, and result in non-uniform dyeing of the surface due to the impact of bubbles on the surface of the workpiece in the dyeing process, thus influencing the final product quality.

In one embodiment, the chemical polishing agent in Step 2) is nitric acid solution.

In one embodiment, sulfuric acid solution is used in the acid tank in Step 3).

In one embodiment, the workpiece is an aluminum or aluminum alloy workpiece. Anti-bacterial anodic oxidation is applicable to both aluminum products and aluminum alloy products.

Embodiment 1

1) pretreatment: remove oil on the workpiece and clean the workpiece; 2) polishing: put the clean workpiece in a nitric acid solution for chemical polishing; 3) anodic oxidation: put the chemically-polished workpiece in a sulfuric acid tank for anodic oxidation; 4) dyeing: put the anodized workpiece in a dye tank which contains a nano-dye, wherein the mass fraction of nano-silver in the dye is 3% and its diameter is 100 nm; 5) sealing: seal the dyed workpiece via a high-temperature hydration or inorganic salt sealing method, and take out the sealed workpiece and dry it after cleaning.

Embodiment 2

1) pretreatment: remove oil on the workpiece and clean the workpiece; 2) polishing: put the clean workpiece in a nitric acid solution for chemical polishing; 3) anodic oxidation: put the chemically-polished workpiece in a sulfuric acid tank for anodic oxidation; 4) dyeing: put the anodized workpiece in a dye tank which contains a nano-dye, wherein the mass fraction of nano-silver in the dye is 5% and its diameter is 80 nm; 5) sealing: seal the dyed workpiece via a high-temperature hydration or inorganic salt sealing method, and take out the sealed workpiece and dry it after cleaning, wherein the inorganic salt used in the inorganic salt sealing method is an acetate.

The above-mentioned embodiments are intended to describe the present invention, but not to limit the structural characteristics of the present invention. Any modifications and polishings made by those skilled in the art shall be included in the patent scope of the present invention. 

What is claimed is:
 1. A method for preparing an anti-bacterial oxide film on the surface of aluminum materials, characterized in that it comprises the following steps: 1) pretreatment: remove oil on the workpiece and clean the workpiece; 2) polishing: put the clean workpiece in an acid solution for chemical polishing; 3) anodic oxidation: put the chemically-polished workpiece in an acid tank for anodic oxidation; 4) dyeing: put the anodized workpiece in a dye tank which contains a nano-dye, wherein the mass fraction of nano-silver in the dye is 3%-5% and its diameter is not more than 100 nm; 5) sealing: seal the dyed workpiece via a high-temperature hydration or inorganic salt sealing method, and take out the sealed workpiece and dry it after cleaning.
 2. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 1, characterized in that an ultrasonic vibration plate is provided at the bottom of the dye tank in Step 4).
 3. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 1, characterized in that a bubble generator is provided at the bottom of the dye tank in Step 4) and dry and clean air is introduced into the bubble generator.
 4. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 3, characterized in that the diameter of the bubbles generated by the bubble generator is not more than 2 mm.
 5. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 1, characterized in that the chemical polishing agent in Step 2) is a nitric acid solution.
 6. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 1, characterized in that a sulfuric acid solution is used in the acid tank in Step 3).
 7. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 1, characterized in that the workpiece is an aluminum or aluminum alloy workpiece.
 8. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 2, characterized in that the workpiece is an aluminum or aluminum alloy workpiece.
 9. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 3, characterized in that the workpiece is an aluminum or aluminum alloy workpiece.
 10. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 4, characterized in that the workpiece is an aluminum or aluminum alloy workpiece.
 11. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 5, characterized in that the workpiece is an aluminum or aluminum alloy workpiece.
 12. The method for preparing an anti-bacterial oxide film on the surface of aluminum materials as claimed in claim 6, characterized in that the workpiece is an aluminum or aluminum alloy workpiece. 